کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8062841 1520635 2018 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow-induced vibrations of two cylinders of different natural frequencies
ترجمه فارسی عنوان
لرزش ناشی از جریان از دو سیلندر فرکانس های طبیعی مختلف
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی دریا (اقیانوس)
چکیده انگلیسی
The paper presents an experimental investigation on characteristics of flow-induced vibrations of two tandem cylinders of different natural frequencies. Both cylinders are allowed to vibrate in the cross-flow direction only. Six different natural frequency ratios fn* (= fn,u/fn,d) = 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 are considered, where fn,u and fn,d are the natural frequencies of the upstream and downstream cylinders, respectively. The spacing ratio L/D (where L is the spacing between the two cylinder centers and D is the diameter) is considered as 1.5 and 2.0. Simultaneous measurements of vibration and frequency responses and vortex shedding frequencies are conducted using laser vibrometers and hotwires, respectively. The results indicate that in the galloping vibration regime there is a critical reduced velocity at which the amplitude of the downstream cylinder drastically jumps and that of the upstream cylinder may drop, depending on fn*. The jump/drop is connected to a lock-in of the vortex shedding with the fifth harmonics of fn,d. The different natural frequencies of the cylinders may suppress both vortex-excited and galloping vibrations of the cylinders at different reduced velocity ranges. The vibration response and its connections with the frequency ratio are elucidated. How the different natural frequencies of the upstream and downstream cylinders affect the vortex shedding frequency in the wake is also illustrated.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ocean Engineering - Volume 155, 1 May 2018, Pages 189-200
نویسندگان
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